Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 26, 2019
Income Tax Disclosure [Line Items]
Employer-paid deferred social security taxes	$ 24.8
Tax depreciation	18.7
Employee retention tax credits	39.2
Prepaid income taxes	18.4	$ 41.6
Gross unrecognized tax benefits	21.6	$ 27.0
Tax position, change is reasonably possible in the next twelve month	6.2
Unrecognized tax benefits, accrued interest	2.1
State loss carryforwards	15.4
Expiring Between 2019 and 2039
Income Tax Disclosure [Line Items]
State loss carryforwards	44.3
Deferred tax assets, federal tax credit carryforwards	63.6
State
Income Tax Disclosure [Line Items]
Prepaid income taxes	7.4
Federal
Income Tax Disclosure [Line Items]
Prepaid income taxes	11.0
Accrued income taxes	$ 6.2